A phthalonitrile resin can be used for various applications. For example, a composite formed by impregnating a filler such as a glass fiber or a carbon fiber with the phthalonitrile resin may be used as a material, such as an automobile, airplane or ship. The procedure for preparing the composite can comprise, for example, mixing a mixture of phthalonitrile and a curing agent or a prepolymer formed by a reaction of the mixture and a filler, and then curing the resulting product. Such content is disclosed in Korean Patent Registration No. 0558158, etc.
To effectively achieve the procedure for preparing the composite, it is required that phthalonitrile as a monomer or a polymerizable composition or a prepolymer formed therefrom has suitable fusibility and fluidity and a so-called process window is wide.
In addition, when the mixture of phthalonitrile and a curing agent or the prepolymer includes voids or generates voids in a procedure of processing or curing, it is possible to cause decrease in the physical properties of the composite, so that such a problem should be also considered.